Improved artificial intelligence discrimination of minor histological populations by supplementing with color-adjusted images.

Despite the dedicated research of artificial intelligence (AI) for pathological images, the construction of AI applicable to histopathological tissue subtypes, is limited by insufficient dataset collection owing to disease infrequency. Here, we present a solution involving the addition of supplemental tissue array (TA) images that are adjusted to the tonality of the main data using a cycle-consistent generative adversarial network (CycleGAN) to the training data for rare tissue types. F1 scores of rare tissue types that constitute < 1.2% of the training data were significantly increased by improving recall values after adding color-adjusted TA images constituting < 0.65% of total training patches. The detector also enabled the equivalent discrimination of clinical images from two distinct hospitals and the capability was more increased following color-correction of test data before AI identification (F1 score from 45.2 ± 27.1 to 77.1 ± 10.3, p < 0.01). These methods also classified intraoperative frozen sections, while excessive supplementation paradoxically decreased F1 scores. These results identify strategies for building an AI that preserves the imbalance between training data with large differences in actual disease frequencies, which is important for constructing AI for practical histopathological classification.

[Malignant Leydig Cell Tumor of the Testis : A Case Report].

A 69-year-old Japanese man was referred to our hospital for a left inguinal testicular tumor and paraaortic lymph node swelling and pleural dissemination. A left orchiectomy was performed in October 2013. Histologically, this testicular tumor was a malignant Leydig cell tumor. The antineoplastic agent mitotan was administered after the orchiectomy. Two months later, although his plasma level of testosterone had de-escalated, the para-aortic lymph node did not decrease in size. A retroperitoneal lymph node dissection was performed in January 2014. Unfortunately, three days after the surgery, the patient died due to disseminated intravascular coagulation and gastrointestinal hemorrhage of unknown cause.

[A case of testicular abscess with low-grade inflammation].

We report a case of testicular abscess with low-grade inflammation. A 55-year-old man was referred to our hospital because of right scrotal pain and swelling for approximately 3 weeks. Physical examination revealed mild tenderness and a hen's egg-sized mass in the right scrotum ; however, fever and scrotal erythema were absent. Magnetic resonance imaging (MRI) showed an enlarged right testis and spermatic cord, and an ultrasonography scan indicated loss of blood flow to these regions. Right testicular necrosis due to spermatic cord torsion or testicular cancer was suspected, and high orchiectomy was performed. However, abscess formation was detected in the testis, and testicular abscess caused by Escherichia coli was diagnosed. The clinical course of this case was unusual because of the small extent of inflammation observed. Typically, testicular abscess is characterized by severe systemic and local inflammation.

Aortic bleeding one week after removal of an intraoperative epicardial temporary pacing wire.

A 56-year-old man had left nephrectomy and resection of a cavoatrial tumor thrombus under a cardiopulmonary bypass assist for left renal cell carcinoma. An intraoperative bipolar temporary epicardial atrial pacing wire was removed on postoperative day 8. The patient collapsed on postoperative day 15. Emergent transthoracic echocardiography and computed tomography scanning with contrast media detected cardiac tamponade. The three-dimensional volume-rendering images from the multislice computed tomography scan demonstrated bleeding from the aortic root. Upon emergency operation, active arterial bleeding from the aortic root distal to the sites of cannulation and cardioplegia was confirmed, and hemostasis with sutures was completed. It is well known that the intraoperative temporary epicardial pacing wire can cause bleeding or arrhythmia, especially when the wire is being removed. However, bleeding usually occurs from the inserted epicardial point of the pacing wire soon after removal of the wire. To our knowledge, this late bleeding complication of the pacing wire is a previously unreported serious iatrogenic complication after cardiac surgery.

[Myeloid sarcoma of the kidney: a case report].

A 40-year-old man was referred to our department for left renal tumor pointed out on a checkup ultrasonography. CT (computed tomography) and MRI (magnetic resonance imaging) demonstrated left renal tumor, clinically T2N0M0. Percutaneous renal needle biopsy was performed because of malignant lymphoma was suspected. Pathological diagnosis was malignant tumor. However, malignant lymphoma could not denied. Therefore, left nephrectomy was performed retroperitonealy. Histological examination revealed myeloid sarcoma of the kidney. Myeloid sarcoma is a rare tumor composed of leukemia cells and usually progresses to acute myelogenous leukemia. To our knowledge, our case is the first report of myeloid sarcoma of the kidney in Japan.

[Metastatic malignant melanoma of the urinary bladder: a case report].

A 62-year-old male underwent resection of malignant melanoma of left breast skin in 2006. In 2007, he underwent lymph node dissection and chemotherapy (DAV-feron therapy) for left axillary lymph nodes metastasis. In Aug 2008, he was referred to our department with chief complaint of macrohematuria. Two non-papillary bladder tumors were detedted on cystoscopy and CT/ MRI showed multiple lymph node swelling, including left inguinal, paraaortic, and right cervical regions. As malignant melanoma cells were found on urinary cytology, a diagnosis of metastatic malignant melanoma of the urinary bladder was made. It was thought that tumor resection would not contribute to prognostic improvement because of multiple lymph node metastases. Therefore, tumor resection was not performed. The patient is currently receiving chemotherapy. This is the eleventh case of metastatic malignant melanoma of the urinary bladder to be reported in the Japanese literature. There have been no previous reports of cases in which urinary cytology was positive for malignant melanoma cells.

A malignant solitary fibrous tumor in the retroperitoneum.

Solitary fibrous tumor in the retroperitoneum is rare. We report a case of a malignant solitary fibrous tumor in the retroperitoneum, with a lymph node metastasis, in a 48-year-old-woman. Computed tomography and magnetic resonance imaging indicated a mass in the retroperitoneal space beside the left kidney, with a swollen paraaortic lymph node. Surgical findings revealed a circumscribed tumor in the retroperitoneum. A pathohistological examination revealed two separate components: a benign hypocellular area rich in collagen fibers and a malignant hypercellular area with nuclear atypia. The histological finding for the lymph node was the same as that in the hypercellular area. Because of these findings, the mass was diagnosed as malignant solitary fibrous tumor. Only surgical treatment was performed, and the patient is alive without recurrence 2.5 years after the surgery. Immunohistochemical staining for p53 was positive in the malignant component but negative in the benign area, indicating that the expression of p53 may play a critical role in the malignant transformation of solitary fibrous tumor.

[Testicular abscess: report of 2 cases].

We report two cases of testicular abscess. The first case is in a 53-year-old man who had been suffering from diabetes mellitus. Because of cerebral infarction, he had been bedridden and a Foley catheter had been indwelt for a long period of time. The second case is in a 78-year-old man who had suffered from acute prostatitis six months earlier. In both cases, the chief complaints were high fever and painful scrotal swelling. At initial evaluation, ultrasonography revealed that the affected testes were swollen without abscess formation and an ipsilateral epididymal swelling was demonstrated in the second case but not in the first case. The urine bacterial culture (UBC) result was positive for Escherichia coli in first case and Pseudomonas aeruginosa in the second case. In both cases, fever and scrotal pain subsided after antibiotic chemotherapy, and inflammatory reactions on routine blood studies were normalized within 2 weeks. Nevertheless, the swollen testes did not sigunificantly reduce in size, and testicular abscess was suspected by magnetic resonance imaging (MRI). Orchiectomy was performed, and intratesticular abscess formations were confirmed macroscopically and microscopically. In each case, bacterial culture from the abscess was positive for the same bacterium as detected from the UBC. It is difficult to distinguish testicular abscess from acute epididymitis at the early stage because of similarities on symptoms or signs between the two. If testicular swelling lasts after appropriate chemotherapy, we believe that attention should be directed to testicular abscess, which needs orchiectomy to obtain a complete cure and MRI is useful in its diagnosis.

Transurethral fulguration for empyema of ectopic ureteral stump.

A 55-year-old woman who had undergone left nephrectomy 7 years prior because of pyonephrosis, suffered from refractory cystitis and was diagnosed with empyema of the left ureteral stump associated with ectopic ureter. Although removal of the stump is a popular treatment for this disease, transurethral fulguration of the stump lumen was performed in the patient described here. The procedure was technically easy and safe, resulting in the disappearance of the dilated stump and cessation of recurring cystitis.

[Pseudotuberculous pyelonephritis associated with staghorn calculus: a case report].

This report describes a 56-year old woman with an unusual form of chronic pyelonephritis mimicking tuberculosis on histopathological findings. She visited our hospital complaining of left flank pain. Left staghorn calculus and retroperitoneal abscess extending from the kidney were demonstrated on CT. No bacteria, including mycobacteria were identified in preoperative urine bacterial culture. Left nephrectomy with drainage of retroperitoneal abscess was performed. Microscopically, the nephrectomy specimen showed caseating granulomas, formed by epitheloid cells, highly suggestive renal tuberculosis. In spite of these findings, acid-fast bacteria were not revealed in the renal lesion nor the abscess, and cultures of the abscess for mycobacteria were also negative. Because of failure of identifying Mycobacterium tuberculosis, this case should be diagnosed as not renal tuberculosis, but pseudotuberculous pyelonehritis, which has been mentioned in recent literatures. Although this disease is not widely recognized, we must be aware of it to avoid unnecessary antituberculous therapy.

[Prostatic cancer with multiple pulmonary metastases treated successfully with hormonal therapy: a case report].

A 66-year-old, man was referred to our hospital for further examination of multiple pulmonary nodules on chest X-ray performed on medical examination. He was referred to our clinic because his chief complaint was poor urinary stream. Prostatic cancer was suspected on digital rectal examination and magnetic resonance imaging. Serum prostatic specific antigen (PSA) level was 134.9 ng/ml. Histological examination of transrectal prostatic sextant biopsy revealed well differentiated adenocarcinoma of prostate. Abdominal computed tomography-scan, gastro-intestinal tract examination and bone scintigraphy demonstrated no other primary lesions or distant metastases. Under the diagnosis of prostatic cancer with multiple pulmonary metastasis, we performed total androgen blockade (TAB) consisting of luteinizing hormone releasing hormone agonist and flutamide following dietylstilbestrol (DES) intravenous injection therapy. After three months, pulmonary nodules disappeared on chest X-ray and PSA level decreased to below 0.1 ng/ml. Pulmonary nodules also disappeared on CT-scan after six months after TAB. He is alive and free from the recurrence for 42 months.